The parallel mechanism is an important development direction of advanced manufacturing, and 2RPS&PSR parallel mechanism is non symmetric mechanism. The Jacobian matrix of the helix theory was used as basis to solve the mechanism, the stiffness of mechanism was obtained. Stiffness analysis was carried out and simulated with Matlab software, and than its various intuitive curve were obtained. It verifies the feasibility of the parallel robot to realize the expected movement, which provides a meaningful reference for the design of this kind of robot, checking and debugging.